In the state of the art a roof antenna module is known, which integrates a microcontroller, in order to transmit communication messages between a transceiver and a communication bus. EP 1 903 632 A1 discloses an antenna module, which has a plurality of transceivers for generating and receiving radio signals from mobile radio, a Wi-Fi (Wireless local area network) and a Bluetooth apparatus. Bus connections are provided such as for a CAN (Controller Area Network), a LIN (Local Interconnect Network), or a MOST bus (MOST—Media Oriented Systems Transport). The communication messages may be transmitted through the antenna module by using different diversity methods, such as a time and frequency division multiplexing.
US 2010/020353 A1 discloses a roof antenna module having an integrated microcontroller. The microcontroller creates a network node for a LAN (Local Area Network). The roof antenna module may also be provided with a radio receiver and the already described transceiver for mobile radio and Wi-Fi. Finally, a GPS receiver (GPS—Global Positioning System) is also provided.
DE 20 2014 003 956 U1 discloses an enclosure for a roof antenna module, in which antennas, transceivers, and a microcontroller may be integrated.
Roof antenna modules which provide a direct coupling of transceivers for radio signals on one hand and digital communication buses of a motor vehicle on the other hand cause a safety hazard for the operation of the motor vehicle. It may happen, for example, that while driving a motor vehicle, a control instruction for activating an emergency brake is sent via radio to the motor vehicle and that this control command is supplied from the roof antenna module to the communication bus of the motor vehicle thus actually causing an unwanted full braking of the vehicle to occur.
The integration of a bus connection into a roof antenna module is nevertheless advantageous, since in this way the cabling requirements for lines for transmitting of high-frequency signals may be reduced.